To boost the uplink capacity, the use of a Spatial Division Multi Access (SDMA) scheme has been found to be useful and is well known as an uplink Multiple Input Multiple Output (MIMO) technique. In such a scheme, the key feature is to schedule more than one user device implementing MIMO functionality on the same communication segment, e.g. a time/frequency slab. The data/information signals from these users can then be separated out at the receiver using standard techniques as Minimum Mean Square error (MMSE) or Successive Interference Cancellation (SIC) techniques. Although the boost in uplink capacity is promising with the application of the above mentioned scheme, various problems exist with such an implementation including higher cost and increased system complexity. Moreover, the performance of such a scheme relies heavily on the difference between the spatial signatures of the users scheduled on the same communication segment. If the users sharing the communications segment, e.g. sharing the same time/frequency slab, happen to have similar spatial signatures, i.e. if the users are not geographically/physically well separated from each other, then transmissions from these users are degraded or unrecoverable due to excessive interference. To address this problem, a complex and more intelligent scheduler might be required to schedule only the users with significantly different spatial signatures, on the same communications segment.
In view of the above discussion, it would be desirable if improved methods and apparatus could be developed to boost the uplink capacity by scheduling more than one user on a single communications segment. It would be beneficial if such improved methods and apparatus were able to boost capacity without adding significant extra complexity to the system.